Odd that I wrote about PPC and landing page optimization today and then stumbled upon this post in my SearchCap newsletter.

I think the true lesson you learned is that even if your PPC campaign looks good, other things can influence its end performance in conversion. The influence can be so great it doesn't matter how well your PPC campaign is put together. Even the most optimal PPC campaign will never convert a user going to a very bad funnel (and the person managing the PPC campaign might think they're just doing a bad job!)

Good work realizing that your PPC spend was inefficient though and being willing to stop it. Keeping track of all the factors that make PPC successful is really difficult and takes a lot of managing.

Since your pain point is your funnel though, the obvious next step would be to fix it. Since your PPC sounds fairly successful right up to conversion, I would take everything you learned from your PPC and apply it to your whole funnel. What messaging was working there? What offers or features got you clicks and how can you emphasize those things throughout your funnel? Carry those winning value propositions on every page and make your visitors feel comfortable and excited about trading their money and personal information for your tools and expertise.

Good luck! It's tough doing these projects, but they're always satisfying when you can show how much improvement you made.